We're sure David Letterman has seen it all by this point, so it's a lot of fun to watch him get so excited about Anna's cup trick — and to see him question whether or not the Oscar-nominated actress has low self-esteem.

"I saw this viral video on Reddit, and it's just this girl doing this thing with the cups and, again, because I'm a huge loser, I thought the best way to spend an entire afternoon would be like watching this video 50 times and teaching myself how to do it," Anna explained. "So when they found out I could do it, they wanted me to do it in the movie."

Noting that this was Anna's second time calling herself a loser, Dave said, "Now I'm beginning to wonder if you have some self-esteem issues."

Anyway, the cup scene became one of Dave's favorites, and he asked her do the trick right on the spot! Anna obliged, and we love the results! Who else is excited to see Pitch Perfect? We definitely are!